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Titolo:
Net accumulation and flux of dissolved organic carbon and dissolved organic nitrogen in marine plankton communities
Autore:
Sondergaard, M; Williams, PJL; Cauwet, G; Riemann, B; Robinson, C; Terzic, S; Woodward, EMS; Worm, J;
Indirizzi:
Univ Copenhagen, Freshwater Biol Lab, DK-3400 Hillerod, Denmark Univ Copenhagen Hillerod Denmark DK-3400 Lab, DK-3400 Hillerod, Denmark Univ Coll N Wales, Sch Ocean Sci, Menai Bridge LL59 5EY, Gwynedd, Wales Univ Coll N Wales Menai Bridge Gwynedd Wales LL59 5EY 5EY, Gwynedd, Wales Univ Paris 06, CNRS, UMR 7621, Observ Oceanol Banyuls, F-66651 Banyuls surMer, France Univ Paris 06 Banyuls sur Mer France F-66651 6651 Banyuls surMer, France Dept Marine Ecol & Microbiol, Natl Environm Res Inst, DK-4000 Roskilde, Denmark Dept Marine Ecol & Microbiol Roskilde Denmark DK-4000 Roskilde, Denmark Plymouth Marine Lab, CCMS, Plymouth PL1 3DH, Devon, England Plymouth Marine Lab Plymouth Devon England PL1 3DH L1 3DH, Devon, England Rudjer Boskovic Inst, Ctr Marine & Environm Res, Zagreb 10000, Croatia Rudjer Boskovic Inst Zagreb Croatia 10000 onm Res, Zagreb 10000, Croatia
Titolo Testata:
LIMNOLOGY AND OCEANOGRAPHY
fascicolo: 5, volume: 45, anno: 2000,
pagine: 1097 - 1111
SICI:
0024-3590(200007)45:5<1097:NAAFOD>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
N-P RATIO; BACTERIAL-GROWTH; SARGASSO-SEA; ENCLOSURE EXPERIMENT; PHYTOPLANKTON; MATTER; BACTERIOPLANKTON; DEGRADATION; RELEASE; BLOOM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
59
Recensione:
Indirizzi per estratti:
Indirizzo: Sondergaard, M Univ Copenhagen, Freshwater Biol Lab, Helsingorsgade 51, DK-3400 Hillerod,Denmark Univ Copenhagen Helsingorsgade 51 Hillerod Denmark DK-3400
Citazione:
M. Sondergaard et al., "Net accumulation and flux of dissolved organic carbon and dissolved organic nitrogen in marine plankton communities", LIMN OCEAN, 45(5), 2000, pp. 1097-1111

Abstract

Marine mesocosms were manipulated with inorganic nutrients over a period of 22 d to investigate organic carbon partitioning under a variety of nutrient regimes. The chemical analyses and biotic measurements included inorganic nutrients, pigment signatures, particulate and dissolved organic species,bacterial production, and community respiration. The biodegradability of dissolved organic carbon (DOC) was investigated with in vitro decomposition experiments. The net particulate organic carbon (POC) production was 50% of the total organic production during the initial 6 d of nutrient-replete growth and during a major diatom bloom. In all other situations the carbon partitioning was strongly in favor of DOC, which accounted for 82 to 111% of the total production. The production of new DOC preceded new DON by about 1 week. Thus,the new dissolved organic matter (DOM) initially had an infinite C:N ratio, which fell to 11-20 when DON started to accumulate. The highest C:N ratiowas measured during a nutrient-replete diatom bloom. Dissolved polysaccharides accounted for 50 to 70% of the new DOC, and the lowest relative amountwas produced during a diatom bloom. The chemical analyses unequivocally demonstrated that carbon partitioning in favor of carbon-rich DOM can take place during an active diatom bloom and not only during the decay of a bloom. The DOC-producing mechanisms cannot be fully identified. However, during the different growth phases the DOC production varied, as did the speciationof DOM with respect to the C:N ratios. When net production of dissolved organic nitrogen (DON) was detected after 11 d, the DON production accounted for 25 to 50% of the daily added and assimilated inorganic nitrogen. The measurements of community respiration made it possible to calculate the maximum carbon recycling by bacteria and bacterial net DOC assimilation. These calculations showed the estimates of carbon partitioning to be very sensitive to bacterial growth yield values and the factors used to convert leucine and thymidine isotope incorporation to bacterial production. Decomposition experiments showed that at least 35% of the new DOC was biodegradable over 10-12 d and that inorganic nutrients only marginally affected use. The calculated turnover times of new DOC were between 15 and 25 d. The semilabile nature of new DOC with respect to microbial attack is suggested as the main reason for the medium-term accumulation of new DOC.

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Documento generato il 15/01/21 alle ore 23:28:39